Pharmacokinetic study on ginsenoside Rg1 and Re in rats following intravenous and oral administration of “Shenmai” injection

Rational: Shenmai injection is derived from traditional Chinese medicine Shenmai San (pulse-activating powder) with main active ingredient extracted from Radix ginseng Rubra and Radix Ophiopogonis. Ginsenoside Rg1 and Re are two major constituents of Radix ginseng Rubra considered responsible for the efficacy of this injection. In the present study, we carried out pharmacokinetics studies on Shenmai injection of ginsenoside Rg1 and Re in rats with oral and intravenous administration to establish bio-analysis methods of Shenmai injection. Methods: The plasma concentration after giving Shenmai injection in two different routes at different time points was analyzed by HPLC method, and pharmacokinetic parameters calculated with pharmacological software DAS3.0 to estimate the oral bioavailability of two components. Results: Ginsenoside Rg1 and Re metabolize faster upon intravenous administration, and in the plasma concentration was untraceable after 6 hours after injection, compared with a much slower absorption when administrated orally, in which the plasma concentration peaked at 8 hours after medication. The bioavailabilities of ginsenoside Rg1 and Re given orally were 7.22% and 7.16%, respectively. Conclusion: The method is specific, simple, sensitive and suitable for the measurement of plasma Rg1 and Re concentrations. Shenmai injection was absorbed slowly by oral administrating with low bioavailability, while intravenous administration manifests superiority of fast onset.